Swapping Speed Sensitive Rack for Base Rack

a3inverter · Post by **a3inverter** » 25 Jun 2019, 08:54

Folks,

A dilemma of sorts. My 2006 base V70 has the speed-sensitive steering rack and it is leaking. I ordered a used one of eBay and got the base rack. My error. It's pristine though, which gives me pause.

Has anyone tried swapping out the SS one for a base one? There's a solenoid, but I believe it's role is to block the flow of PS fluid once the car has reached a certain rate of speed.

I believe all the other dimensions are the same - given that both racks were options for these cars.

Wondering if the solenoid and CANBUS would be happy if I just pulled the solenoid out of the control value, left it plugged in and grounded it so it could keep operating as before. It wouldn't actually perform any function WRT the power steering rack.

Thoughts?

Post by **abscate** » 25 Jun 2019, 10:42

Totally an idiot on speed sensitive racks, but I can't imagine the solenoid just blocks flow,

My guess it bypasses flow from the rack so that you only get assist when closed. If you pull it out, I think you will have no assist at all, and would have to plug the hole in the rack of course.

Can you test it to see if its normally open or closed valve function?

On edit....my idiocy isrevealed in this post, best ignored

a3inverter · Post by **a3inverter** » 25 Jun 2019, 10:50

Thanks Abscate.

Agreed on the theory of operation - my expectation is that the solenoid leverages a vehicle speed signal to interrupt assist (flow from the pump). At high speeds, no assist, at low speeds, assist.

A point of clarification - I am talking about taking out the current speed sensitive rack and replacing it with the base rack. I'd retain the solenoid (secure it with a zip tie) and keep it plugged in to its harness.

The solenoid would continue to receive signal with this setup, but wondering if it needs to be grounded.

I will look around in VIDA for wiring diagrams...

a3inverter · Post by **a3inverter** » 25 Jun 2019, 16:23

Looks like it's driven by the Power Steering Unit...

Post by **abscate** » 25 Jun 2019, 19:59

Duh on me. Your writing above was clear, I just man-brained it.

You do have a Lin bus connect To the PSU so that might be interrogating that sensor for data. It’s not just analog stuff

MDK · Post by **MDK** » 26 Jun 2019, 05:16

Well... that's really it isn't abscate.... normally open/ normally closed. The racks are extremely high pressure and trying to plug it may be... well a bad idea. Just thinking about swapping out the rack....eh. If was me I'd try to return the wrong one and get the right one and be done with it. Or put it on Matthews parts for sale list.options...options...options

Post by **abscate** » 26 Jun 2019, 05:25

The new rack doesn’t have a port to plug up, so OP proposes just letting solenoid operate in free space, covered up and secure of course.

Does anyone have info if the rack can bolt on as a direct replacement?

SteveV70 · Post by **SteveV70** » 02 May 2023, 21:51

resurrecting an old thread here. My problem is the exact opposite….my car is non assisted steering and I was sent a speed sensitive assist rack,…with the solenoid. The rack is in great shape, and came off a car with 100K miles so it’s hard not to use it. I can’t see where it would be a problem to install it. Anyone have an opinion on that? The solenoid wouldn’t have anything hooked up to it, and the car certainly doesn’t know/care that it’s there. Has anyone done this?

hetschaap · Post by **hetschaap** » 16 Jun 2023, 02:09

a3inverter wrote: ↑25 Jun 2019, 16:23 Looks like it's driven by the Power Steering Unit...

Actually, after looking at the diagram, i think it can be done (not that it is relevant anymore). Component 6/71 is a valve (also depicted by the symbol; an electronically operated valve). It does not contain a sensor, nor is there any other sensor (or electronics) on the powersteering unit, pump, lines, hoses or reservoir itself. The valve directs high-pressure fluid in low speed situations to the rack, and diverts the high pressure fluid internally in the rack back to the reservoir. I'd therefore say that indeed a speed sensitive power steering rack can be replaced by a non-speed sensitive rack, maybe even without connecting the valve (although that may cause a DTC to pop up due to infinite resistance over the two terminals normally connected to the valve).

Post by **Krons** » 16 Jun 2023, 05:25

SteveV70 wrote: ↑02 May 2023, 21:51 resurrecting an old thread here. My problem is the exact opposite….my car is non assisted steering and I was sent a speed sensitive assist rack,…with the solenoid. The rack is in great shape, and came off a car with 100K miles so it’s hard not to use it. I can’t see where it would be a problem to install it. Anyone have an opinion on that? The solenoid wouldn’t have anything hooked up to it, and the car certainly doesn’t know/care that it’s there. Has anyone done this?

I think it would work. Only thing to watch for is it may be twitchy at speed or take a lot of turns at slow speed. That comment is assuming the solenoid controls flow to change the lock to lock number of turns based on speed—you obviously would not have that.